In a person acclimatized for high altitude, O2 saturation is maintained because of:

Acclimatization to altitude occur due to a variety of compensatory mechanisms. Secondary to acclimatization there is an increase in red blood cell 2,3 DPG which in turn decrease the oxygen affinity of hemoglobin. This decrease in oxygen affinity increases the availability of oxygen to tissues. Must know: Changes occurring during Acclimatization: Hyperventillation results in respiratory alkalosis Increase in 2,3 BPG which decreases the affinity of oxygen affinity of hemoglobin. This inturn shift the oxygen dissociation curve to the right. Increase in erythropoetin level Increase in red blood cell count and hemoglobin Ref: Human Adaptation Rev By A. Robeo Frisancho, page 244-8